This invention relates generally to communication systems and, more particularly, to the distributed power control of two or more powered systems.
Trains are commonly used as an efficient means for hauling cargo and/or passengers over long distances. A typical train includes a plurality of non-powered rail cars and a plurality of locomotives for moving the non-powered rail cars over a track. Two or more locomotives grouped or otherwise controlled together for traction purposes are commonly referred to as a “consist.” Distributed power control systems (hereinafter distributed power, or DP systems, or simply DP) allow for the operation of one or more remote locomotives (or group of locomotives forming a consist) in a train. The remote locomotive(s) are remotely controlled from a lead locomotive of the train by way of a radio or hard-wired communication system. Currently, DP systems operate with only a single version of DP software installed, identified by a version code. The version code is used during the linking process to ensure that only compatible locomotives with the same version code are linked and operated together. For example, a locomotive from Railroad “A” will have one type of software or a unique version code whereas a locomotive from Railroad “B” will have another software or a distinct version code. Since the two locomotives are different, the two types or versions of software are different and will not operate together.
When locomotives are upgraded to a newer or different version of DP software, a new version code is provided which in turn prohibits linking and/or operation with locomotives that have an older and/or a different version of DP software. Therefore, to provide for complete linkability, all locomotives must to have the same version of DP software. To have the same version of DP software available for all locomotives, upgrades to locomotives, which are typically linked together, would have to be completed at approximately the same time. Due to scheduling constraints, owners and operators of locomotives may have a limited timeframe to perform the upgrades.
Within the United States, DP control is provided using a Federal Communication Commission (FCC)-approved frequency allocated for railroad operations in the 450 MHz frequency range at power levels of about 30 watts. Similarly, for DP systems used in other countries, other frequency allocations and power levels have been provided. DP radio systems are capable of providing reliable and accurate locomotive control during conditions when the radio channel is free of interference. However, when interference is present, special communication techniques or radio message formats, such as unique locomotive identifiers and time randomization, have been developed to mitigate communication conflicts, such as may be encountered in situations where a large number of locomotives are operated within a relatively small geographical area. Examples of small geographical areas include, but are not limited to, a location within a train yard, industrial site, etc.
Providers of DP control systems currently have been able to rework DP control systems to support two different locomotive types so that they could operate together in the same train. A common message format for both different locomotive types has been further developed to ensure communication between two different locomotive types, or version codes. However, when an upgraded locomotive is placed in the same train as a locomotive of the same type which has not been upgraded, then the upgraded locomotive type must be able to operate in the non-reworked state using the original message format and version codes in order to allow the two locomotives to operate together in the same train. Also, when it is desirable to include additional locomotive types that must operate together in the same train, reworking existing DP control systems becomes cost prohibitive, since such changes require significant more time to accomplish establishing a workable linking scheme between three or more different types of DP control systems.
Owners and operators of locomotives that are linked in a DP train configuration would benefit from having a DP control system where more than two versions of DP software is workable with a specific DP train and where radio message formats are provided to insure communication between lead and remote locomotives, where the remote locomotives may include more than two locomotive types. Having such a DP control system would allow owners and operators to more effectively schedule upgrades, thus resulting in minimized downtime for a fleet of locomotives. Owners and operators will also recognize benefits by having a greater range of locomotive combinations to be used in a single DP train configuration. Likewise, since DP-type control systems may be used with other powered systems, owners and operators of other powered systems would also realize cost savings where a DP-type control system existed which could operate with various versions of DP-like software used on powered systems that are linked together to complete a mission.